<!DOCTYPE html>
<link rel='stylesheet' href='./one-style.css'>
<div>BFCached</div>
<script>
  window.didShow = new Promise(f => window.addEventListener('pageshow', event => {
    console.log(event);
    window._persisted = !!event.persisted;
    window._event = event;
    f({ persisted: !!event.persisted });
  }));
</script>
